This is the 35 USC 371 national stage of international application PCT/SE98/02195 filed on Dec. 1, 1998, which designated the United States of America.
The present invention relates to a retraction device for hoses and cables used in a milking robot.
Modem dairies often use milling robots to milk the dairy animals. A typical milking robot comprises a stallxe2x80x94where the animal stands while being milked, and a robot arm-which moves various tools from a parked idle position on the wall of the stall to a working position under the udder of the animal. These tools such as teat cleaning devices, premilking cups and milking cups can be connected by hoses or cables to various services such as, for example, a cleaning fluid supply, a power supply e.g an electrical cable, high-pressure hydraulic fluid, a flexible rotation shaft etc., a compressed air supply, a vacuum supply or a waste fluid collecting system Thus a tool with suitable cables and hoses can be moved from the parking position by the robot arm to a working position under the animal. When the tool is positioned under the udder the hoses and cables extend from the wall of the stall along the floor of the stall to the udder and the tool can be dislodged from the robot, or the hoses and cables damaged, if the animal moves or kicks the cable or hose. To reduce the risk of this happening each hose and cable or bundle of hoses can be fitted with a retraction spring which holds the hose or cable taut in the air. This however has the disadvantage that the forces on the robot arm vary as the cable or hose is pulled out or retracted and this makes it more difficult to accurately position the robot arm Furthermore if the spring force is made sufficiently large enough to return the tool to its parked position if it is dislodged from the robot arm then the power and strength of the robot arm must be increased which leads to a larger, heavier and more expensive arm. If the spring force is not sufficient to return the dislodged tool to its parking position then an alarm to call for manual assistance must be provided.
The object of the present invention is to provide milking tool retraction means which overcome the problems of the prior art.
In accordance with the invention, this object is achieved in a milking robot of the above kind by providing the cables or hoses with a counteract system able to normally only counteract the weight of the cable or hose but which is also capable of automatically counteracting the weight of the tool if it is dislodged from the robot arm.
In a preferred embodiment of the invention the counteract system is also able to assist in parking of tools.
This system has the advantage that in normal use the loads on the robot arm are minimised while permitting automatic parking of a dislodged tool.